Fake bake.

Thinking about hitting the tanning salon for some summer like sun? Several new studies found that 30 to 40 percent of white teen girls have "fake baked" at least once, and many of them are hooked on it. It's not just girls, either: One study found that 11 percent of white teen guys have soaked up rays in a tanning bed, too.

The problem: Tanning beds can give you a lot more than just a tan. They wrinkle skin much too soon, weaken the skin's ability to fight infection, and may double your risk for skin cancer. "There's no such thing as a safe tan," says Dr. Albert Yan, a dermatologist (skin doctor) at the Children's Hospital of Philadelphia.

That's because tanning beds emit the same ultraviolet (UV, invisible radiation) rays as the sun. UV rays penetrate skin and wreak havoc on your cells' delicate chemistry--they can even damage your DNA (chemical blueprint for all life). Special cells in the epidermis (see diagram, right) try to block UV rays by releasing melanin (brown-colored chemical pigment) to dye your skin. A suntan is actually a sign that your skin is damaged.

Sun damage adds up over a person's lifetime, so it's important to limit the harm when you're young. "Your skin has a certain memory and never completely heals from sun damage," says Yan. So leave the baking to the holiday turkey.